1. Field of the Invention
The present invention relates generally to an antenna device, and more particularly, to an antenna device of a mobile terminal that can change a monopole type antenna to a Planar Inverted-F Antenna (PIFA) by grounding one side of the monopole type antenna to a battery cover composed of a metal material in order to secure radiation performance of the mobile terminal when the battery cover composed of a metal material is fixed to the mobile terminal.
2. Description of the Related Art
In accordance with user demand, mobile terminals have decreased size and thickness and provide various functions according to a digital convergence trend. For example, mobile terminals provide a service using a communication function such as digital broadcasting reception, Global Positioning System (GPS), Bluetooth, Radio Frequency Identification (RFID), and mobile commerce. The mobile terminal providing the communication function has one or more antennas. The antenna efficiently transmits or receives a signal in order to perform wireless communication.
Since mobile terminals have decreased in size and thickness, housings of the mobile terminals have reduced in strength. In order to solve the strength problem of the mobile terminal housing, the mobile terminal housing is composed of a metal material. However, the mobile terminal housing composed of a metal material adversely affects radiation performance of the antenna. Particularly, when a battery cover composed of a metal material is positioned adjacent to the antenna, a parasitic resonance occurs, whereby radiation performance of the antenna deteriorates. Therefore, when using a mobile terminal housing composed of a metal material, an antenna device in which radiation performance of the mobile terminal does not deteriorate is desirable.